Últimos itens adicionados do Acervo: Universidade Católica de Temuco

A Universidade Católica de Temuco é uma institução privada confessional do Chile, fundada pelo bispo Alejandro Menchaca Lira em 1959.

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‣ Landscape Dynamics for the period 1980-2004 in the Budi River and Lake coastal basin, Chile : Considerations for the conservation of its wetlands

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
The landscape corresponds to a complex, open, space-time system, intermediate between nature and society. Its conditions and dynamics are determined by natural processes and human presence in which local and regional alterations modify ecological processes and patterns of biodiversity. Conspicuous in the Budi lake/river basin landscape are continental wetlands and marshy bodies of water and forests. Conflicts have arisen due to substitution and land-use change. Using the framework and scale of analysis of landscape ecology, the landscape dynamics of the Budi lake/river basin has been analyzed as an input for ecological planning of this area and conservation of its wetlands. Studies of variation of areas destined for different uses and land cover, as well as rate of change starting from category maps drawn up on the basis of photo-interpretation of aerial photographs of the area under study taken in 1980, 1994 and 2004, were done. Eight landscape types were identified, starting from previously drawn up classifications of ground cover and land-use. We also evaluated the variation in landscape patterns through the application of 21 measuring processes related to typology and surface, perimeters, shapes, diversity, aggregation and adjacency as indicators of landscape dynamics and evolution...

‣ Comparative karyology of lentic and lotic populations of Diplodon chilensis chilensis (Bivalvia: Hyriidae)

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
The mean karyotypes of four populations of Diplodon chilensis chilensis (Gray, 1828) (two lentic and two lotic) inhabiting the south of Chile are described and compared. Chromosomes were obtained by squash of cleaving embryos, previously treated with colchicine, fixed in ethanol-acetic acid 3:1 at 4°C, and stained using the Feulgen reaction. The karyotype of the four populations is 2n = 34, with metacentric and submetacentric chromosomes. In the population from the Peu-Peu stream, the centromeric position in two chromosome pairs (3 and 10) differs significantly from that in the corresponding pairs from the other populations. Karyotype findings of this study do not support the proposal that the differences described between lentic and lotic populations of D. ch. chilensis may result from genetic differentiation among populations. This study is an initial contribution to the knowledge of cytogenetic characteristics in Chilean populations of Diplodon chilensis chilensis.

‣ Fenoles solubles totales y su relacion con la inhibicion de la rizogenesis en estacas de Nothofagus pumilio (Poepp. et Endl.) Krasser

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
Los compuestos fenólicos en concentraciones altas participan como inductores de la oxidación de auxinas, interfiriendo con la formación de raíces adventicias en estacas de tallo. Al no obtener enraizamiento en estacas de lenga (Nothofagus pumilio (Poepp. et Endl.) Krasser) en invierno y verano, se atribuyó que esto se debía a una alta cantidad de fenoles producidos en lenga, comparado con otros Nothofagus. En este estudio se procedió a cuantificar el contenido de fenoles solubles totales en estacas de lenga a través del método analítico Folin-Dennis, y comparar con el contenido de fenoles solubles totales en raulí (Nothofagus alpina (Poepp. et Endl.) Oerst.), especie que sí forma raíces adventicias. El contenido de fenoles solubles obtenidos en N. pumilio fue mayor (2254 ± 296 ppm ) que en N. alpina (1978 ± 137 ppm) (P<0.05). Los resultados coinciden con la propuesta que la no formación de raíces adventicias en estacas de lenga sería influida por altas concentraciones de fenoles, siendo necesario continuar con esta investigación en el sentido de identificar tipos de fenoles y comprobar in vitro el efecto de los fenoles como inductores de la actividad enzimática responsable de la oxidación de la auxina.; The failure to obtain rooting in cuttings of lenga (Nothofagus pumilio (Poepp. et Endl.) Krasser)...

‣ Effect of aerial exposure on physiological condition and survival of Diplodon chilensis (Bivalvia: Hyriidae) during translocation

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português

‣ Fractioning and soluble protein free phenols recovery from lenga (Nothofagus pumilio) cuttings

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
At present, there is no information about Nothofagus fractioning and protein recovery from cutting crude extracts; necessary condition to, in vitro, demonstrate enzymatic activity with cofactors presence. Besides, this information is crucial to determine enzymatic expression levels, which in turn could allow to know physiological aspects of lenga (Nothofagus pumilio), cuttings which could be conditioning the poor results obtained in rooting treatments. To obtain information about what was pointed out above, a protocol which not only allows to separate phenol free proteins from crude extracts of lenga cuttings, but to determine its composition as well, was validated and standardized. From each of the 60 samples, 36 fractions were analyzed, obtaining, repetitively, phenol free proteins from fraction 14 on. The results obtained were statistically validated and show that the method employed allows to fractionate and to recover phenol free proteins from lenga cuttings through a Sephadex G-50 column (P < 0.05).; Para Nothofagus spp. no existe a la fecha información acerca del fraccionamiento y recuperación de proteínas a partir de extracto crudo de estacas, condición necesaria para demostrar in vitro actividad enzimática en presencia de cofactores. Además...

‣ ¿Cómo podemos intervenir para fortalecer el clima educativo en tiempos de innovación?

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
The present investigation corresponds to the work of a Doctoral Thesis, developed with the University of Seville, Spain, research which in its final stages also became a DGIUCT investigation by the General Research Department of the Catholic University of Temuco. Using a qualitative-quantitative method it consists of four correlative stages. The first concerns the development of a questionnaire for the Educative Environment, the second concerns the exploration of Educative Environment consulting 404 teachers and directives. The third and fourth stages involve the use of ?natural semantic networks? and ?discussion groups?. The results have been revealing, for example, all types of establishment show evidence that the most important factor in the perception of the environment are the ?interpersonal teaching relationships?, with this being more important for teachers than their own relationship with students and parents.; La presente investigación corresponde al trabajo de Tesis Doctoral, desarrollado en la Universidad de Sevilla, España, investigación que en sus últimas fases se enmarca además en una investigación DGIUCT de la Dirección General de Investigación de la UC de Temuco. De diseño cualitativo-cuantitativo, está constituida por cuatro fases correlativas. La primera corresponde a la construcción de un instrumento para Clima Educativo...

‣ Cold plasma ashing improves the trace element detection of single Daphnia specimens by total reflection X-ray fluorescence spectrometry

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
The recently developed dry method for the element determination of single freshwater microcrustacean specimens (Daphnia) using total reflection X-ray fluorescence (TXRF) spectrometry showed that inhomogeneities of the biological material on the glass carriers resulted in some cases in high background and hampered the detection of certain trace elements (e.g. Cr, Ni). The aim of this study was to test how inhomogeneities of the biological material can be reduced using cold plasma ashing (CPA) techniques. For that, single specimens of the microcrustacean Daphnia pulex prepared according to the dry method were measured by TXRF before and after CPA. To determine the efficiency of the removal of organic matrix, the background and signal-to-background relationship of 28 samples were analyzed. The results showed (1) a highly significant reduction of the background by CPA fluctuating between 26 and 46% (all elements) and (2) a significant increase of the signal-to-background relationship by the factor 1.5-2.5 (all elements) and a much better detection of Cr, Pb, As and Se. The element concentrations (with exception of Cr, Ni and Pb) after ashing were in the same range or slightly higher than that before ashing. No significant differences between the two treatments were observed for Mn...

‣ Determination of trace elements in planktonic microcrustaceans using total reflection X-ray fluorescence (TXRF): First results from two Chilean lakes

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
First results are described from the application of a recently developed dry method for determination of elements in single specimens of freshwater microcrustaceans, using total reflection X-ray fluorescence spectrometry (TXRF). This method is a powerful, non-destructive technique for quantifying the trace element content of minute biological samples with a dry weight of 3-50 μg. Three different freshwater microcrustaceans were sampled, from the natural, uncontaminated Lake Laja and from the artificial Rapel reservoir which is slightly contaminated by drainage water from a copper mine. Single specimens of Daphnia pulex, Bosmina chilensis, and Ceriodaphnia dubia were prepared using a modification of the dry method and measured by TXRF. The results showed that both As, Mn, Fe, Ni, Zn, and Cu content and the bioaccumulation of these metals were usually significantly different between the microcrustaceans from the two lakes. The largest difference was found for Cu which was eight times more concentrated in the two microcrustaceans from Rapel reservoir than it was in D. pulex from Lake Laja.

‣ La evaluación del paisaje: Una herramienta de gestión ambiental

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
El paisaje es la expresión espacial y visual del medio. Es un recurso natural escaso, valioso y con demanda creciente, fácilmente depreciable y difícilmente renovable. El paisaje visual considera la estética y la capacidad de percepción por un observador. Para evaluar un paisaje existen diferentes métodos y procedimientos; aquí se propone un método mixto con valoración directa de subjetividad representativa y análisis posterior indirecto con análisis de componentes principales. El método propuesto intenta mejorar el problema de la subjetividad con grupos de evaluadores cuya opinión global sea representativa y es valorado con instrumentos que contienen listas de adjetivos con expresión numérica que facilita su procesamiento. En el análisis de componentes principales sí participan paneles de expertos. La técnica de valoración del paisaje es el análisis de preferencias, que parte aceptando que el valor de un paisaje está en función del número de individuos que le prefieren. También se describe un método para valorar la fragilidad del paisaje, que integrado a la valoración permite aplicar criterios de preservación y conservación. Una evaluación equivaldrá a una fotografía instantánea, que podrá ser comparada con una fotografía homóloga del futuro. Esto permitirá cuantificar las pérdidas (o ganancias) de paisajes valiosos...

‣ Salinity effects on the abundance of Boeckella poopoensis (Copepoda, Calanoida) in saline ponds in the Atacama desert, northern Chile

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
The calanoid copepod, Boeckella poopoensis Marsh, 1906 inhabits shallow saline ponds located in the Andes mountains in Argentina, Bolivia, Chile, and Peru, as well as in the plains of southern Argentina. The species is halophilic and can tolerate salinity levels of 1 to 90 ppt. This paper describes the relative abundance of the species in shallow mountain ponds in northern Chile from 23° to 27°S. A direct correlation was observed between salinity and the relative abundance of B. poopoensis (r2 = 0.4139), and between 45 and 90 ppt S the species was found to be dominant in zooplankton assemblages. Crustacean species richness at the sites studied showed a significant, inverse trend with salinity (r2 = 0.7329), and this trend became even stronger (r2 = 0.7681) when data previously published for the Bolivian Andean plateau were included. Ecological and biogeographical issues related with these results are discussed.

‣ Phase partition of gaseous hexane and surface hydrophobicity of Fusarium solani when grown in liquid and solid media with hexanol and hexane

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
The filamentous fungus, Fusarium solani, was grown in liquid and solid culture with glucose, glycerol, 1-hexanol and n-hexane. The partition coefficient with gaseous hexane (HPC) in the biomass was lower when grown in liquid medium with 1-hexanol (0.4) than with glycerol (0.8) or glucose (1) The HPC for surface growth were 0.2 for 1-hexanol, 0.5 for glycerol, 0.6 for glucose, and 0.2 for F. solani biomass obtained from a biofilter fed with gaseous n-hexane. These values show a 200-fold increase in n-hexane solubility when compared to water (HPC = 42). Lower HPC values can be partially explained by increased lipid accumulation with 1-hexanol, 10.5% (w/w) than with glycerol (8.5% w/w) or glucose (7.1% w/w). The diameter of the hyphae diminished from 3 μm to 2 μm when F. solani was grown on solid media with gaseous n-hexane thereby doubling the surface area for gaseous substrate exchange. The surface hydrophobicity of the mycelia increased consistently with more hydrophobic substrates and the contact angle of a drop of water on the mycelial mat was 113° when grown on n-hexane as compared to 75° with glucose. The fungus thus adapts to hydrophobic conditions and these changes may explain the higher uptake of gaseous hydrophobic substances by fungi in biofilters.

‣ Clinal variation and selection on MDH allozymes in honeybees in Chile

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
Evidence of clinal variation and selection on Mdh-1 locus was observed in 27 samples from 22 sites in a 2800 km north-south transect across Chile. We found a negative correlation among F allele normalized frequency and mean temperature, and minimum temperature of January and July, as well as a positive correlation among S allele normalized frequency and annual mean, and minimum January temperatures. Our results lend weight to the idea that Chilean honeybee populations of colder areas have higher F allele frequencies, supporting previous claims that Mdh-1 allozymes of Apis mellifera are subject to temperature-mediated selection.

‣ Medición post-ejercicio de variables fisiológicas, hematológicas y bioquímicas en equinos de salto holsteiner

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
A post-exercise study was carried out on 10 Holsteiner horses through measurements of physiological, hematological and biochemical variables. Blood samples were obtained at rest and immediately after exercise, every 15 days, during 2 months (day 0 to day 60). The mean and standard deviation were calculated and the two-way analysis of variance and the Tukey test were carried out to determine if there were statistically significant differences between at rest v/s postexercise; resting at the different samplings (day 15 to day 60) v/s resting at day 0 and postexercise at the different samplings (day 15 to day 60) v/s postexercise at day 0, as consequence of training. The heart rate and breathing frequency were significantly smaller (P<0.05) in the postexercise measurement once concluded the period of training v/s the postexercise at the day 0. Likewise, the recovery was significantly faster at day 60 v/s days 0. The packed cell volume (PCV) and the hemoglobin (HB) were significantly greater (P<0.05) at the postexercise of the last sampling (day 60) v/s the postexercise of the first sampling (day 0). The total proteins, blood glucose and the aspartateaminotransferase did not show statistically significant changes. The plasma activity of creatinkinase increased after the exercise was performed v/s resting. This increase was only statistically significative (P<0.05)...

‣ Lattice-Boltzmann permeability of sphere packs undergoing diagenesis

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
For a broad range of applications the most important transport property of porous media is permeability. Here we calculate the permeability and porosity of ordered sphere packs, simple, body-centered and face-centered cubic, as simple diagenetic processes reduces their pore spaces. For diagenesis we use simple geometrical models including compaction by plastic deformation, compaction by pressure solution, consolidation of cementation, consolidation by surface precipitation and temporary consolidation by capillary action until porosity becomes isolated. For flow simulations at selected porosity levels we use the lattice-Boltzmann method with a 15-speed and 19-speed models on three dimensional lattices. For validation purposes, the lattice-Boltzmann method is compared against an explicit finite-difference method for incompressible flow in simpler geometries. Simulating slow creeping flow through three-dimensional channels of different polygonal cross sections and three-dimensional porous structures of intermediate complexity checked the accuracy of the lattice-Boltzmann scheme used. We explore pore space microstructure transitions and universal character of the permeability-porosity relationships obtained.

‣ Valores educativos mapuches para la formación de persona desde el discurso de kimches

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
This article shows those educative values used in teaching mapuche children and teenagers through the kimche speech. A critical analysis of their speech is made on the basis of respect and affection categories. The hypothesis is that the kimche speech contains the foundations, values and purposes of mapuche education. Therefore, the aim is, on one hand, to identity those values in the frame of mapuche speech and social memory which support that knowledge. On the other hand, to show the perception they have about schooling process of mapuche students. The sample is composed by kimches of the following territorialities: Lafquenche, Nagche, Huilliche and Huenteche.; El objetivo de este artículo es develar aquellos valores educativos que se utilizan en la formación de niños y adolescentes mapuches a través del discurso de kimches (sabios mapuches). Con este propósito, se realiza un análisis crítico del discurso basado en las categorías respeto y afecto. Se postula la hipótesis de que el discurso de los kimches contiene los fundamentos, valores y finalidades de la educación mapuche. Por lo tanto, se busca identificarlos en el marco del discurso y de la memoria social mapuche que sustentan dichos conocimientos. Se busca, además...

‣ New effects during steam gasification of naphthalene: The synergy between CaO and MgO during the catalytic reaction

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
The catalytic activity of commercial CaO and MgO and their physical mixtures on the gasification reactions with steam was studied. Steam gasification of naphthalene as model reaction was selected and experiments in a laboratory scale reactor were performed. Carbon conversion for pure MgO and CaO was 54 and 62%, respectively. Every mixture showed a larger conversion than the weighted average of the pure compounds conversions; i.e., they exhibited catalytic synergy. The largest catalytic activity, reflected by the carbon conversion (79%), was obtained with a 10%CaO+90%MgO mixture, which also showed the highest catalytic synergy (44.2%) among the assayed mixtures. Characterization of catalysts by XPS, XRD, SBET and DTG/DTA lead to conclude that formation of new phases, sintering, modification of dehydration or carbonation of the oxides in the mixture could not explain synergy, or basicity changes. Oxides forming the mixture have not been modified by the preparation or during the catalytic gasification. A catalytic cooperation between the two separated oxides is observed. Thus, synergy is attributed to MgO presence in the mixture, which inhibits formation of carbonaceous material as well as bidentate carbonate in the CaO surface, while promotes the formation of unidentate carbonate of lesser stability at the reaction temperature and in the presence of H2O(v).

‣ Catalytic oxidation of emissions in combustion systems for forest biomass, using catalysts with TiO2 support

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
A study was made of the catalytic oxidation of a model mixture of effluents from forest biomass combustion equipment, consisting principally of methane (CH4), naphthalene (C10H8), carbon monoxide (CO) and oxygen-poor air (10% O2, balance N2), in a laboratory reactor, using MeOx/TiO2 catalysts (Me = Fe, Cu or Mn), prepared using incipient wetness impregnation. It was observed that the addition of metal oxides to the TiO2 increases catalytic activity in the combustion of all the contaminants present in the model effluent (CH 4, C10H8 and CO). The catalysts were characterised using the following techniques: SBET, XRD, DTG/DTA and TPD-NH 3; and from these it was observed that the support presented only the anatase phase in all the catalysts, despite having been subjected to temperatures in excess of 1.000 K during combustion. The highest acidity among all the solids tested, measured by TPD-NH3, was obtained for the FeOx/TiO2 catalysts, which were also those which showed the greatest catalytic activity. This high level of activity may be related to the formation of isolated metallic phases; i.e. hematite (Fe2O3), which would be the active phase in the combustion of C10H8 and CH4. On the other hand, with to respect to the 5 % wt. values of Me/TiO2 (Me: Fe...

‣ The use of a portable total reflection X-ray fluorescence spectrometer for trace element determination in freshwater microcrustaceans (Daphnia)

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
The suitability of a newly developed, portable total reflection X-ray fluorescence (TXRF) spectrometer (PicoTAX, Roentec, Berlin, Germany) to analyze trace elements in biological material was tested and compared with a stationary instrument (Spectrometer 8030 C, FEI, Munich, Germany). For that, single freshwater microcrustacean specimens (Daphnia spec.) with dry weights ranging between 1.6 and 18.8 μg individual-1 were prepared according to the dry method and analyzed with both instruments. Additionally, for orientation purposes, freshly collected Daphnia were prepared in field according to the wet method directly on the glass carrier and analyzed using the portable PicoTAX. For method validation, certified reference material (CRM 414, plankton) was analyzed. The results of the in-field measurements demonstrate that the PicoTAX yields very fast and sufficiently sensitive in-field measurements on the element content of minute biological samples. For As, Cu, K, Mn, Ni and Sr, a good correlation was found between the two spectrometers. Only for Ca, Fe, Pb and Zn the comparison with the results of the stationary equipment has shown significant differences.

‣ Remote lab experiments: Opening possibilities for distance learning in engineering fields

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
Remote experimentation laboratories are systems based on real equipment, allowing students to perform practical work through a computer connected to the internet. In engineering fields lab activities play a fundamental role. Distance learning has not demonstrated good results in engineering fields because traditional lab activities cannot be covered by this paradigm. These activities can be set for one or for a group of students who work from different locations. All these configurations lead to considering a flexible model that covers all possibilities (for an individual or a group). An inter-continental network of remote laboratories supported by both European and Latin American institutions of higher education has been formed. In this network context, a learning collaborative model for students working from different locations has been defined. The first considerations are presented.

‣ Genetic characterization of a polymorphic dipeptidyl aminopeptidase of Apis mellifera

Fonte: Universidade Católica de Temuco Publicador: Universidade Católica de Temuco
Tipo: Artículo de Revista
Português
Dipeptidyl aminopeptidase (DAP) activity towards L-leucylglycine-β- naphthylamide (Leu-Gly NA) was characterized in pupae and adult extracts of Apis mellifera. Enzyme activity was more conspicuous in pupae than in adult extracts and it seemed to be concentrated in digestive tract tissues. Two genetically determined electrophoretic variants were observed in honeybee samples from the USA and Chile; in Brazilian Africanized bees, two additional variants were observed. Segregational analyses showed no close linkage between Dap and Est-1, Lap D, Pgm-1, cd, and Ac loci of Apis mellifera.